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Puja S
Ranch Hand

Joined: Jan 06, 2005
Posts: 51
Hi,

Which of the following class instance creation expressions would generate a compile-time error?

a. new Short(1)
b. new Short('1')
c. new Short('b' - 'a')
d. new Short((short)1 - (short)2)
e. new Short((byte)1)
f. new Short((short)1)

This question is from Dan.....I am able to understand that a,b,c,d are the answers,but I am not able to understand,why is e not an answer ?

Thanks.
Mike Gershman
Ranch Hand

Joined: Mar 13, 2004
Posts: 1272
why is e not an answer?


The compiler will provide an implicit narrowing cast for an assignment of a constant expression that will fit in the left-hand operand. This is not available for arguments of methods or constructors.

The available constructors for class Short require a short or a String.

With "new Short((byte)1)", the argument has been explicitly cast to a byte. Going from a byte to a short is a widening conversion, not a narrowing cast, and perfectly legal for an argument.
[ January 18, 2005: Message edited by: Mike Gershman ]

Mike Gershman
SCJP 1.4, SCWCD in process
 
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subject: java.lang